1Heat oven to 350ºF. Grease bottom only of rectangular pan, 13x9x2 inches, or spray with cooking spray.
2Stir brownie mix, water, oil and eggs in medium bowl until well blended. Stir in 1 cup crushed cookies. Spread in pan.
3Bake 24 to 26 minutes or until toothpick inserted 2 inches from side of pan comes out clean or almost clean. Cool completely, about 1 hour. In small microwavable bowl, microwave frosting uncovered on High about 10 to 15 seconds or until drizzling consistency. Drizzle frosting over brownies. Sprinkle with 2/3 cup chopped cookies. For 20 brownies, cut into 5 rows by 4 rows.